Pulmonary Function Testing

Flashcards covering key vocabulary, tests, and concepts related to Pulmonary Function Testing, obstructive and restrictive lung diseases, and lung volumes/capacities.

Pulmonary Function Testing (PFT)

A diagnostic tool used to identify and quantify changes in pulmonary function due to disease, evaluate therapy, perform epidemiological surveillance, assess postoperative risks, and determine pulmonary disability.

Obstructive Disease

A major category of pulmonary disease characterized by increased airways resistance.

Restrictive Disease

A major category of pulmonary disease characterized by a decrease in lung compliance and lung volumes.

Spirometer

A volume-measuring device used in pulmonary function testing.

Pneumotachometer

A flow-measuring device commonly used in pulmonary function testing.

Pulmonary Mechanics Tests

Measurements that assess the ability of the lungs to move large volumes of air quickly through the airways, including Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), other forced expiratory flow measurements, and Maximum Voluntary Ventilation.

Forced Vital Capacity (FVC)

The most common test of pulmonary mechanics, an effort-dependent maneuver that measures the total volume of air exhaled after a maximal inspiration.

Forced Expiratory Volume in 1 second (FEV1)

The volume of gas exhaled in the first one second of the Forced Vital Capacity (FVC) maneuver.

FEV1/FVC Ratio

A calculated value obtained by dividing the largest FEV1 by the largest FVC, used to distinguish between obstructive and restrictive lung disease patterns.

FEF200-1200

The average flow rate early in the FVC maneuver, measuring the flow between 200 ml and 1200 ml of exhaled air.

FEF25-75

A measure of flow during the middle 50% of the FVC.

Maximal Voluntary Ventilation (MVV)

An effort-dependent test reflecting patient effort, respiratory muscle function, chest wall expansion ability, and airway patency, performed by breathing deep and fast for 12 seconds.

Lung Volumes

Basic subdivisions of total lung capacity, including Tidal Volume, Inspiratory Reserve Volume, Expiratory Reserve Volume, and Residual Volume.

Lung Capacities

Combinations of two or more lung volumes, including Total Lung Capacity, Inspiratory Capacity, Functional Residual Capacity, and Vital Capacity.

Tidal Volume (VT)

The volume of air inhaled or exhaled with each normal breath, typically 500-700 ml.

Residual Volume (RV)

The volume of air remaining in the lungs after a maximal exhalation.

Total Lung Capacity (TLC)

The total volume of air contained in the lungs after a maximal inspiration, normally about 6 L.

Functional Residual Capacity (FRC)

The volume of air remaining in the lungs at the end of a normal expiration, calculated as Expiratory Reserve Volume + Residual Volume.

Vital Capacity (VC)

The maximum volume of air that can be exhaled after a maximal inspiration, normally about 4.8 L in adults.

Helium Dilution

A technique to measure Residual Volume (RV) based on the dilution of a known amount of helium by the patient’s RV.

Nitrogen Washout

A technique to measure Residual Volume (RV) based on the fact that 79% of RV is nitrogen; the volume of nitrogen exhaled divided by 0.79 equals RV.

Body Box (Plethysmography)

A technique to measure Residual Volume (RV) that applies Boyle’s law.

Diffusing Capacity (DLCO)

A measurement of the lungs' ability to transfer gas (often carbon monoxide) from the air in the lungs to the red blood cells in the pulmonary capillaries. Results are reported in ml/min/mm Hg.

Emphysema

A common cause of reduced DLCO, characterized by a decrease in surface area for gas exchange.

Pulmonary Fibrosis

A common cause of reduced DLCO, characterized by a thickened alveolar-capillary (AC) membrane.